Take the time to do the blocking right. Snow Loads. Roofing Loads. Maintence Workers. Falling trees and branches. You never know when the ceiling or roof will be stressed. What is not sagging today might in three years if the conditions are just right.
None of those apply. Any of those roof loads are transferred to load bearing walls. It is very unlikely that a non-load bearing wall will protect anything. Even if a branch managed to happen to miss all load bearing structures and hit the non-load bearing wall..it is typically only supported with 3/4" ply..how much protection does that serve?
You can do like RSCB shows, but there is more there than really needed. You could do something like these:
-blue is the hidden joists (back under the walls)
- red is exposed
- black is blocking (16" o.c.)
or something like this..
The cross-hatched areas would be 3/4" ply, say 6" or 8" wide. Spread wood glue and place under the seams. Screw plywood on each side of the seam to laminate the patch to the existing ply.
You can do either way or some combination of the two. The idea is to support the seam to prevent deflection there.